EP1415616A1 - Implant delivery system with marker interlock - Google Patents

Abstract

An implant delivery system is disclosed. The delivery system includes anelongated member having an implant mounting location. A self-expandable implantis mounted at the implant mounting location. The implant is held in a compressedorientation by a retractable sheath. An interlock structure prevents the implant fromdeploying prematurely as the sheath is retracted. The interlock structure includesradio-opaque markers that identify the position of the implant.

Description

TECHNICAL FIELD

This invention pertains to a system for delivering an implant to a site in a bodylumen. More particularly, this invention pertains to a delivery system for a self-expandableimplant such as a stent.

BACKGROUND

Stents are widely used for supporting a lumen structure in a patient's body.For example, stents may be used to maintain patency of a coronary artery, other bloodvessels or other body lumen.

Stents are commonly metal, tubular structures. Stents are passed through abody lumen in a collapsed state. At the point of an obstruction or other deploymentsite in the body lumen, the stent is expanded to an expanded diameter to support thelumen at the deployment site.

In certain designs, stents are open-celled tubes that are expanded by inflatableballoons at the deployment site. This type of stent is often referred to as a "balloonexpandable" stent. Other stents are so-called "self-expanding" stents. Self-expandingstents do not use balloons to cause the expansion of the stent. An example of a self-expandingstent is a tube (e.g., a coil tube or an open-celled tube) made of anelastically deformable material (e.g., a superelastic material such a nitinol). This typeof stent is secured to a stent delivery device under tension in a collapsed state. At thedeployment site, the stent is released so that internal tension within the stent causesthe stent to self-expand to its enlarged diameter. Other self-expanding stents are madeof so-called shape-memory metals. Such shape-memory stents experience a phasechange at the elevated temperature of the human body. The phase change results inexpansion from a collapsed state to an enlarged state.

A delivery technique for elastically deformable stents is to mount thecollapsed stent on a distal end of a stent delivery system. Such a system wouldinclude an outer tubular member and an inner tubular member. The inner and outertubular members are axially slideable relative to one another. The stent (in thecollapsed state) is mounted surrounding the inner tubular member at its distal end. The outer tubular member (also called the outer sheath) surrounds the stent at thedistal end.

Prior to advancing the stent delivery system through the body lumen, a guidewire is first passed through the body lumen to the deployment site. The inner tube ofthe delivery system is hollow throughout its length such that it can be advanced overthe guide wire to the deployment site.

The combined structure (i.e., stent mounted on stent delivery system) is passedthrough the patient's lumen until the distal end of the delivery system arrives at thedeployment site within the body lumen. The deployment system and/or the stent mayinclude radiopaque markers to permit a physician to visualize positioning of the stentunder fluoroscopy prior to deployment.

At the deployment site, the outer sheath is retracted to expose the stent. Theexposed stent is now free to self-expand within the body lumen. Following expansionof the stent, the inner tube is free to pass through the stent such that the deliverysystem can be removed through the body lumen leaving the stent in place at thedeployment site.

In prior art devices, the stent may prematurely deploy as the outer tube isretracted. Namely, with the outer tube partially retracted, the exposed portion of thestent may expand resulting in the remainder of the stent being squeezed out of theouter tube. This can result in the stent being propelled distally beyond a desireddeployment site. Also, once the stent is partially unsheathed, it is sometimesdetermined that the stent placement needs to be adjusted. With existing systems, thisis difficult since the stent has a tendency to force itself out of the sheath therebymaking adjustments difficult. What is needed is a system that retains the stent on thecatheter even when a majority of the stent has been exposed by retraction of thesheath, and allows a stent to be re-sheathed even after a majority of the stent has beenexposed by retraction of the sheath.

Also, in existing systems, it is difficult to accurately determine the position ofthe stent. What is also needed is a system that provides an accurate visible indicatorof the position of the stent.

SUMMARY

One aspect of the present disclosure relates to an implant delivery system thatprovides enhanced placement control of the implant.

Examples of a variety of inventive aspects are set forth in the description thatfollows. It is to be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only and are notrestrictive of the broad inventive aspects disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a side elevation view of one embodiment of a stent delivery systemhaving features that are examples of inventive aspects in accordance with theprinciples of the present disclosure;

Fig. 2 is an enlarged view of the distal end of the system of Fig. 1 with anouter sheath shown in phantom line;

Fig. 3 is the view of Fig. 2 with the outer sheath retracted;

Fig. 4 is a plan view of one embodiment of a stent having an interlockgeometry that interlocks with an interlock structure of a delivery system, the stent andthe interlock structure are shown cut longitudinally and laid flat with an axialseparation between the stent proximal end and the mating interlock structure;

Fig. 5 is the view of Fig. 4 with the stent proximal end and mating interlockstructure shown interlocked;

Fig. 6 is a plan view of the stent shown in Fig. 4 with a second embodiment ofan interlock structure, the stent and the interlock structure are shown cutlongitudinally and laid flat with an axial separation between the stent proximal endand the mating interlock structure;

Fig. 7 is the view of Fig. 6 with the stent proximal end and mating interlockstructure shown interlocked;

Fig. 8 is a plan view of the stent shown in Fig. 4 with a third embodiment of amating interlock structure, the stent and the interlock structure are shown cutlongitudinally and laid flat with an axial separation between the stent proximal endand the mating interlock structure;

Fig. 9 is the view of Fig. 8 with the stent proximal end and mating interlockstructure shown interlocked;

Fig. 10 is a plan view of the stent shown in Fig. 4 with a fourth embodiment ofa mating interlock structure, the stent and the interlock structure are shown cutlongitudinally and laid flat with an axial separation between the stent proximal endand the mating interlock structure;

Fig. 11 is the view of Fig. 10 with the stent proximal end and mating interlockstructure shown interlocked;

Fig. 12 is a plan view of the stent shown in Fig. 4 with a fifth embodiment of amating interlock structure, the stent and the interlock structure are shown cutlongitudinally and laid flat with an axial separation between the stent proximal endand the mating interlock structure;

Fig. 13 is the view of Fig. 12 with the stent proximal end and mating interlockstructure shown interlocked;

Fig. 14 is a plan view of another embodiment of an alternative stent having aninterlock structure that interlocks with an interlock structure of a six embodiment of amating interlock structure, the stent and the interlock structure are shown cutlongitudinally and laid flat with an axial separation between the stent proximal endand the mating interlock structure; and

Fig. 15 is the view of Fig. 14 with the stent proximal end and mating interlockstructure shown interlocked.

DETAILED DESCRIPTION

With reference now to the various drawing figures in which identical elementsare numbered identically throughout, a description is provided of embodiments thatare examples of how inventive aspects in accordance with the principles of the presentinvention may be practiced.

I.Delivery System

Figs. 1-3 show astent delivery system 10 having features that are examples ofhow certain inventive aspects in accordance with the principles of the presentdisclosure may be practiced. Thesystem 10 has distal andproximal ends 11, 13, andincludes aninner member 14 and a retractableouter sheath 16 that slides over theinner member 14. Astent mounting location 26 is located adjacent the distal end 11of thesystem 10. A stent 12 (visible in Figs. 2 and 3) is carried at the stent mountinglocation of thestent delivery system 10 in a collapsed (or reduced diameter) state.Thestent 12 mounts over theinner member 14 and is covered by thesheath 16 so asto be retained in the collapsed state (see Fig. 2). Thestent 12 is released (i.e.,deployed) by retracting thesheath 16 to uncover or expose the stent 12 (see Fig. 3).Thesystem 10 includes aninterlock structure 27 that prevents thestent 12 from prematurely deploying. Upon release of thestent 12 from thestent delivery system10, thestent 12 expands to an enlarged diameter to abut against the walls of thepatient's lumen in order to support patency of the lumen. The expansion of thestent12 also causes thestent 12 to disengage from theinterlock structure 27.

Thesystem 10 is sized to be advanced through the patient's body lumen. Inuse, thesystem 10 is preferably sufficiently long for the distal end 11 to be placed atthe deployment site in the patient's body lumen with theproximal end 13 remainingexternal to the patient's body for manipulation by an operator.

Thesheath 16 of thesystem 10 may have a variety of different constructions.In one embodiment, the sheath has a tubular construction of braid-reinforced polyesteradapted to resist kinking and to transmit axial forces along the length of thesheath 16.Thesheath 16 may be constructed so as to have varying degrees of flexibility along itslength.

Theinner member 14 of thesystem 10 is relatively flexible and can be madeof a polymeric material such as nylon. In one embodiment, theinner member 14 hasa tubular configuration and defines a lumen that extends through an entire length oftheinner member 14. This type of configuration allows the system to be passed overa guidewire for guiding the system to a desired deployment location. However, inother embodiments, theinner member 14 can have a solid, non-tubular configuration.

The distal end 11 of thesystem 10 includes a tapered and flexibledistal tipmember 30 that is sufficiently flexible to permit advancement of thestent deploymentsystem 10 through the patient's lumen while minimizing trauma to the walls of thepatient's lumen. Thetip 30 is connected to theinner member 14 adjacent thestentmounting location 26.

Theproximal end 13 of thesystem 10 includes a manifold housing 20connected to a lock housing 22. Thesheath 16 connects to the manifold housing 20.Astrain relief jacket 24 surrounds thesheath 16 adjacent its connection to the housing20 to provide strain relief for thesheath 16. Theinner member 14 passes throughboth the manifold housing 20 and lock housing 22. An outer reinforcingmember 32surrounds and is bonded to theinner member 14 adjacent theproximal end 13 of thesystem 10. The reinforcingmember 32 is preferably made of a relatively rigidmaterial such as stainless steel. Aport housing 34 is bonded to the reinforcingmember 32. Theport housing 34 has a bore aligned with an inner lumen of theinnermember 14 and functions to facilitate access to the inner lumen.

The manifold housing 20 carries anadmission port 42 for injecting a contrastmedia into the interior of the manifold housing 20. The interior of the manifoldhousing 20 is preferably in fluid flow communication with a passage between theinner member 14 and thesheath 16. In use, the contrast media can be directed fromthe passage into the patient's body lumen through discharge ports (not shown).

The lock housing 22 carries a threaded locking member (or lock nut) 46 whichcan be turned to engage the reinforcingmember 32. Thelock nut 46 selectivelypermits and fixes axially movement between of the inner member and the sheath.Relative movement between the inner member and the sheath is permitted to define atransport position and a deploy position of thesystem 10.

First andsecond handles 48, 50 are secured to the lock housing 22 andreinforcingmember 32, respectively. In the transport position, thehandles 48, 50 arespaced apart and thesheath 16 covers thestent mounting location 26 to preventpremature deployment of thestent 12. When thehandles 48 and 50 are moved towardeach other, thesheath 16 slides rearwardly or proximally relative to theinner member14. In other words, relative axial movement between thehandles 48, 50 (representedby arrow A) results in relative axial movement between theinner member 14 and thesheath 16. In particular, thesheath 16 slides rearwardly from the transport position tothe deploy position to fully expose thestent mounting location 26 and permit thestent12 to freely expand toward its fully expanded diameter. After such expansion, thestent delivery system can be proximally withdrawn through the expanded stent andremoved.

A stent delivery system is also described in U.S. Patent Application Serial No.09/954,555, filed September 17, 2001, that is hereby incorporated by reference in itsentirety.

II.Overview of Example Interlock Configurations

Thestent delivery system 10 is adapted for delivery of a stent to a deploymentsite in a body lumen of a patient's body. By way of non-limiting, representativeexample, the stent may be a self-expanding stent having a construction such as thatshown in U.S. Pat. No. 6,132,461. In one non-limiting embodiment, the stent can bemade of a superelastic metal such as nitinol, or the like. The stent may also be a coilstent or any other self-expanding stent. Another representative stent is shown inUnited States patent application Serial No. 09/765,725, filed January 18, 2001 and entitled STENT, which is hereby incorporated by reference. It is also contemplatedthat certain inventive aspects in accordance with the principles of the presentinvention are also applicable to balloon expandable stents. It will be appreciated thatthe inventive concepts disclosed herein are not limited to the particular stentconfigurations disclosed herein, but are instead applicable to any number of differentstent configurations.

A concern with existing delivery systems for self-expanding stents is controlof stent delivery. For example, due to their elastic characteristics, self-expandingstents have a tendency to propel themselves axially outwardly from their restrainingsheaths before the sheaths have been completely retracted. When this occurs, controlof stent placement is compromised since the stent may overshoot the desireddeployment site. Further, once the stent has been completely deployed, subsequentadjustment of the stent deployment location can be difficult because re-sheathingtypically cannot be readily accomplished.

To address the above concerns, thedelivery system 10 is preferably equippedwith an interlock configuration (e.g.,interlock structure 27 of Figs. 2 and 3) thatconstrains relative axial movement between thestent 12 and theinner member 14until after thesheath 16 has been fully retracted. For example, when thestent 12 ismounted on theinner member 14 and restrained in the compressed orientation by thesheath 16, a first interlock geometry located at aproximal end 12a of thestent 12interlocks with a second interlock geometry (e.g., interlock structure 27) adjacent thestent mounting location 26. The interlock geometries remain interlocked to constrainaxial movement of thestent 12 until after the sheath has been retracted beyond apredetermined location (e.g., theproximal-most end 12a of the stent 12). When thesheath 16 has been retracted beyond the predetermined location, the interlockgeometry of thestent 12 is allowed to expand. As the interlock geometry of the stentexpands, the first interlock geometry of thestent 12 disengages from the secondinterlock geometry thereby allowing theinner member 14 of thesystem 10 to bemoved axially relative to the stent without interference from the interlock geometries.

Figs. 4-15 show 6 different interlock configurations. In each of the Figures 4-13,thestent 12 is depicted. In Figs. 14 and 15, a modifiedstent 612 is depicted. Inall of the Figs. 4-15, proximal ends 12a, 612a of therespective stents 12, 612 areshown in relation to corresponding stent interlock structures (e.g.,structures 27, 227,327, 427, 527, 627). As can be understood, the stent interlock structures are located adjacent thestent mounting location 26 ofstent delivery system 10. Thestructures27, 227, 327, 427, 527 and 627 are preferably fixedly attached to theinner member 14adjacent the mountinglocation 26. For example, thestructures 27, 227, 327, 427, 527and 627 can be bonded, crimped, swaged, affixed, fastened, fused, molded in,embedded in, or otherwise secured to theinner member 14. In each of the pairedFigures (i.e. Figs. 4-5, 6-7, 8-9, 10-11, 12-13 and 14-15), the stent and the stentinterlock structure have been cut longitudinally and laid flat. In the first Figure ofeach pair (e.g. Fig. 4), the stent interlock structure and the stent are shown disengagedfrom one another. In the second Figure of each pair (e.g. Fig. 5), the stent interlockstructure and the stent are shown interlocked. In all Figures 4-15, the stents aredepicted in the reduced diameter configuration. In all of Figures 4-15, theinnermember 14 and thesheath 16 have been omitted for clarity.

While all of the embodiments depicted herein include stent retainers in theform of separate interlock pieces secured to theinner member 14, the invention is notso limited. For example, stent-retaining structures having interlocks can also beformed as an integral/unitary structure with the inner member.

III.Example Stent Configuration

Referring to Figs. 4 and 5, thestent 12 of Figures 2 and 3 is depicted. Thestent 12 has a length L and a circumference C, and includes a plurality of struts 86(i.e., reinforcing members). At least some of thestruts 86 have free terminal ends 72that define proximal anddistal ends 12a and 12b of thestent 12.

Thestent 12 includes an interlock geometry in the form ofenlargements 74positioned at the free terminal ends of thestruts 86. As shown in Fig. 4, theenlargements are circular enlargements. It will be appreciated that other shapes andinterlock configurations could also be used. Theenlargements 74 includeinterlockportions 88 that project outwardly from thestruts 86 in a circumferential direction(i.e., in a direction coinciding with the circumference C of the stent 12).

In one embodiment, thestent 12 can be manufactured by cutting (e.g., lasercutting) the various features from a solid tube of material. When manufactured bythis technique, theenlargements 74 do not project radially beyond an inner and outerdiameter of the stent.

In the illustrated embodiment, thestent 12 includes radiopaque markers 18that permit a physician to accurately determine the position of thestent 12 within the patient's lumen under fluoroscopic visualization. The markers 18 are preferablylocated adjacent the proximal anddistal ends 12a, 12b of the stent. The markers 18can be attached to thestent 12 by techniques such as adhesive, heat fusion,interference fit, fasteners, intermediate members or other techniques. Materials formaking the radiopaque marker should have a density suitable for visualizationthrough fluoroscopic techniques. Preferably, the markers have a radiopacitysubstantially greater than the material forming the struts of the stent. Exemplarymaterials comprise tantalum, platinum, gold, tungsten and alloys of such metals. Insome embodiments, the markers can be coated with a radiopaque material or filledwith a radiopaque filler.

In the illustrated embodiments shown in Figs. 4-13, the markers 18 are at leastpartially defined at the interlock geometries located at the ends of thestent 12. In oneembodiment, theenlargements 74 may define openings in the form of through-holesor through-apertures (i.e., holes that extend completely through the enlargements 74)within which the markers 18 may be positioned. For example, markers in the form ofinsert pieces can be press-fit or riveted within the through-holes. A process formounting markers within through-holes is disclosed in U.S. patent application SerialNo. not yet assigned, entitled Method of Securing Radiopaque Markers to an Implant,having Attorney Docket No. 11576.69US01, filed on a date concurrent herewith, theapplication being incorporated herein by reference in its entirety. In anotherembodiment, the enlargements may include openings in the form of recesses(depressions that extend partially through the enlargements) within which the marker18 may be placed. Positioning the markers 18 on theends 12a, 12b of thestent 12provides precise stent location information to a physician, even after deployment andremoval of the stent delivery device.

IV. First Embodiment of Delivery System Interlock

Referring again to Figs. 4 and 5, theinterlock structure 27 of Figs. 2 and 3 isdepicted in isolation from theinner member 14 and thesheath 16. Theinterlockstructure 27 includes a collar orband 68 the having adistal edge 29 facing theproximal end 12a ofstent 12. Interlock structures in the form of receptacles 84 (i.e.,sockets, openings, keyways, pockets, etc.) are defined adjacent theedge 29. Thereceptacles 84 are defined by partitions 66 that extend axially from theband 68. Thepartitions 66 each have a retainingstructure 67 including extensions 67a, 67b that extend outwardly from the partitions 66 in opposite circumferential directions so as topartially encloseadjacent receptacles 84. Thereceptacles 84 are configured to receivetheenlargements 74 of thestent 12.

The geometry of thereceptacles 84 is selected to mate with the predeterminedgeometry of the stentproximal end 12a such that thestent 12 and theinterlockstructure 27 can be axially coupled or interlocked when thestent 12 is compressed atthe mountinglocation 26. For example, similar to the enlargements 82, thereceptacles 84 are shown having generally rounded or circular shapes. In the firstembodiment shown in Figs. 4 and 5, thereceptacles 84 are each sized to receive andinterlock with a pair ofenlargements 74. When a pair ofenlargements 74 arereceived within areceptacle 84, the extensions 67a, 67b of the retainingstructures 67oppose and circumferentially overlap theinterlock portions 88 of the enlargement 74(see Fig. 5) such that the stent is restricted from distal movement relative to thecollar27.

Eachreceptacle 84 defines anentrance opening 58 having first dimension d1(Fig. 4) that extends between the corresponding extensions 67a, 67b. Outer edges ofthestruts 86 of the pair of male interlock structures 82 define a second dimension d2.In one embodiment, the first dimension d1 is less than the second dimension d2.Thus, when thestent 12 is interlocked with theinterlock structure 27, thestruts 86corresponding to each pair ofenlargements 74 are compressed together in acircumferential direction by contact with the extensions 67a, 67b of theretainers 67.Thus, thestruts 86 corresponding to thesame receptacle 84 are flexed togethercausing theenlargements 74 within thereceptacle 84 to be moved closer together.Concurrently, struts 86 corresponding toadjacent receptacles 84 are flexed apartthereby widening a spacing between theircorresponding enlargements 74. Thisoccurs in part becauseretainers 67 have a dimension d3 that is larger than adimension d4 between thestruts 86. As shown in Fig. 3, when the structures 82 areflexed toward one another a visible gap G may be formed between thestruts 86. Bythis configuration, the size of theenlargement 74 can be increased to accommodatelarger sized markers 18 to assist in stent observation and placement. Withoutproviding this configuration, increasing the size of the markers 18 would requirelessening the material thickness of the partitions 66. In other embodiments, thereceptacles can be sized to receive more than two enlargements.

With the specific embodiment shown, thestent 12 andinterlock structure 27are coupled such that thestent 12 andstructure 27 are restricted from relative rotarymotion (i.e., about axis X - X) and relative axial motion when thestent 12 is in thecollapsed state. The predetermined stent geometry and the complementary matinggeometry of theinterlock structure 27 do not restrict relative radial motion. Namely,as the self-expandingstent 12 expands radially, theenlargements 74 are free toradially move out of thereceptacles 84. After such motion, thestent 12 is no longercoupled to theinterlock structure 27.

V.Second Embodiment of Delivery System Interlock

Referring now to Figs. 6 and 7, asecond interlock structure 227 adapted foruse with the delivery system of Figs. 1-3 is shown. Similar to theinterlock structure27, theinterlock structure 227 is configured to interlock with theproximal end 12a ofthestent 12. Theinterlock structure 227 includesreceptacles 84 sized for receiving apair ofenlargements 74, and at least onereceptacle 284 sized to receive asingleenlargement 74. This type of embodiment is useful where a stent having an oddnumber of enlargements is used.

VI.Third Embodiment of Delivery System Interlock

Referring now to Figs. 8 and 9, athird interlock structure 327 adapted for usewith the delivery system of Figs. 1-3 is shown. Similar to theinterlock structure 27,theinterlock structure 327 is configured to interlock with theproximal end 12a of thestent 12. Theinterlock structure 327 defines asingle receptacle 384 sized to receiveand interlock with a single one of the plurality ofenlargements 74.

In the illustrated embodiment of Figs. 8 and 9, thereceptacle 384 is defined bypartitions 366 extending outward from amain band 368. Thepartitions 366 includeonlyinward extensions 367, as no outward extensions are provided to define adjacentinterlock structure. Thepartitions 366 can have a dimension d5 greater than a spacingd6 between theenlargements 74 to cause theenlargements 74 other that the onereceived in thereceptacle 384 to be circumferentially compressed together when thepieces are interlocked. It is contemplated that other embodiments can include morethan onereceptacle 384 defined bypartitions 366 having onlyinward extensions 367.

VII.Fourth Embodiment of Delivery System Interlock

Referring now to Figs. 10 and 11, afourth interlock structure 427 adapted foruse with the delivery system of Figs. 1-3 is shown. Similar to theinterlock structure27, theinterlock structure 427 is configured to interlock with theproximal end 12a ofthestent 12. Theinterlock structure 427 includes aninterlock member 466 thatinterlocks between a pair ofenlargements 74 of thestent 12. Theinterlock member466 defines asingle receptacle 484 that receives all of theenlargements 74 of thestent 12.

In the embodiment of Figs. 10 and 11, themember 466 has afirst extension467a and a second extension 467b. Theextensions 467a, 467b of theinterlockmember 466 function to oppose and circumferentially overlap portions of theenlargements 74 (see Fig. 11) to restrict distal movement of thestent 12 relative to theinterlock structure 427. Themember 466 defines a dimension d3 greater than adimension d4 between the struts. This variance in dimensions causes at least some oftheenlargements 74 to be compressed together in a circumferential direction withinthereceptacle 484.

VIII.Fifth Embodiment of Delivery System Interlock

Referring now to Figs. 12 and 13, afifth interlock structure 527 adapted foruse with the delivery system of Figs. 1-3 is shown. Similar to theinterlock structure27, theinterlock structure 527 is configured to interlock with theproximal end 12a ofthestent 12. Theinterlock structure 527 includesreceptacles 584 corresponding toeach of theenlargements 74 of thestent 12. Eachreceptacle 584 is sized to receive asingle one of theenlargements 74.

IX.Sixth Embodiment of Delivery System Interlock

Referring now to Figs. 14 and 15, asixth interlock structure 627 adapted foruse with the delivery system of Figs. 1-3 is shown. Theinterlock structure 627 isadapted to interlock withenlargements 674 of analternative stent 612. In theillustrated embodiment of Figs. 14 and 15, theenlargements 674 are in the form ofoblong projections. The oblong projections include interlock portions 688 that projectoutwardly fromstruts 86 in a circumferential direction (i.e., in a direction coincidingwith the circumference C of the stent 612). The interlock portions 688 includeinterlock surfaces 690 that face in a distal direction. Unlike theprevious stent 12embodiment, thestent 612 does not include markers at theenlargements 674.

Theinterlock structure 627 defines areceptacle 684 sized to receive asingleenlargement 674. Thereceptacle 684 is defined by partitions 666 having onlyinwardextensions 667. When interlocked, theextensions 667 oppose and circumferentiallyoverlap the interlock surfaces 490 of the enlargements 474 (see Fig. 15). Thus, thestent is restricted from distal movement relative to theinterlock structure 627 whenthe two components are interlocked.

It is contemplated that more than one of thereceptacles 684 can be used.Further, it is also contemplated that the partitions 666 can include outward extensionsto define adjacent receptacles having the oblong configuration. Moreover, similar toat least some of the previous embodiments, the partitions 666 can have a dimensionthicker that a corresponding dimension between thestruts 86 to cause at least some oftheenlargements 674 to be compressed together in a circumferential direction whenthestent 12 and theinterlock structure 627 are interlocked.

X.Other Embodiments

The depicted embodiments show that the interlock between thestent 12 andtheinner member 14 is provided at theproximal end 12a of thestent 12. It will beappreciated that for certain embodiments, the interlock between theinner member 14and thestent 12 can be provided at the distal end 12b of the stent 12 (e.g., for adistally retractable sheath). Moreover, while the embodiments shows interlockstructures (e.g., enlargements) provided at all of the proximal ends of thestruts 86, theinvention is not so limited. For example, in some embodiments, only some of thestruts 86 may include interlock structures.

While the various embodiments of the present invention have related to stentsand stent delivery systems, the scope of the present invention is not so limited. Forexample, while particularly suited for stent delivery systems, it will be appreciatedthat the various aspects of the present invention are also applicable to systems fordelivering other types of self-expandable implants. By way of non-limiting example,other types of self-expanding implants include anastomosis devices, blood filters,grafts, vena cava filters, percutaneous valves, or other devices.

It has been shown how the objects of the invention have been attained in apreferred manner. Modifications and equivalents of the disclosed concepts areintended to be included within the scope of the claims.

Claims (18)

1. A medical device comprising:

   an implant including a plurality of struts having terminal ends, at leastsome of the terminal ends of the struts including enlargements, the implantalso including radiopaque markers positioned within at least some of theenlargements; and

   an implant delivery system including an inner member and an outersheath that mounts over the inner member, the delivery system including animplant mounting location at which the implant mounts, the outer sheath beingmovable from a transport position where the sheath covers the implant at theimplant mounting location, to a deploy position where the implant is exposed,the implant delivery system further including an interlock structure forpreventing premature deployment of the implant, the interlock structuredefining a receptacle for receiving at least one of the enlargements.
2. The medical device of claim 1, wherein the receptacle receives at leasttwo of the enlargements.
3. The medical device claim 2, wherein the enlargements arecircumferentially compressed together within the receptacle.
4. The medical device of claim 2, wherein the receptacle receives morethan two of the enlargements.
5. The medical device of claim 1, wherein the delivery system includes aplurality of receptacles for receiving the enlargements.
6. The medical device of claim 5, wherein the delivery system includes aseparate receptacle for each of the enlargements.
7. The medical device of claim 5, wherein each of the receptaclesreceives at least two of the enlargements.
8. The medical device of claim 5, wherein at least one of the receptaclesreceives at least two of the enlargements, and at least one of the receptaclesreceives only a single one of the enlargements.
9. The medical device of claim 1, wherein at least some of theenlargements define openings, and wherein the radiopaque markers includeinserts positioned within the openings.
10. The medical device of claim 9, wherein the openings include through-holes.
11. A medical device comprising:

    an implant including a plurality of struts having terminal ends, at leastsome of the terminal ends of the struts including enlargements; and

    an implant delivery system including an inner member and an outersheath that mounts over the inner member, the delivery system including animplant mounting location at which the implant mounts, the outer sheath beingmovable from a transport position where the sheath covers the implant at theimplant mounting location, to a deploy position where the implant is exposed,the implant delivery system further including an interlock structure forpreventing premature deployment of the implant, the interlock structuredefining a receptacle for receiving at least two of the enlargements.
12. The medical device claim 11, wherein the enlargements arecircumferentially compressed together within the receptacle.
13. The medical device of claim 12, wherein the receptacle receives morethan two of the enlargements.
14. The medical device of claim 11, wherein the delivery system includesa plurality of receptacles for receiving the enlargements.
15. The medical device of claim 14, wherein each of the receptaclesreceives at least two of the enlargements.
16. The medical device of claim 15, wherein at least one of the receptaclesreceives at least two of the enlargements, and at least one of the receptaclesreceives only a single one of the enlargements.
17. A medical device comprising:

    an implant including a plurality of struts having terminal ends, at leastsome of the terminal ends of the struts including enlargements; and

    an implant delivery system including an inner member and an outersheath that mounts over the inner member, the delivery system including animplant mounting location at which the implant mounts, the outer sheath beingmovable from a transport position where the sheath covers the implant at theimplant mounting location, to a deploy position where the implant is exposed,the implant delivery system further including an interlock structure forpreventing premature deployment of the implant, the interlock structuredefining a single receptacle for receiving a single one of the enlargements.
18. A medical device comprising:

    an implant including a plurality of struts having terminal ends; and

    an implant delivery system including an inner member and an outersheath that mounts over the inner member, the delivery system including animplant mounting location at which the implant mounts, the outer sheath beingmovable from a transport position where the sheath covers the implant at theimplant mounting location, to a deploy position where the implant is exposed,the implant delivery system further including an interlock structure forpreventing premature deployment of the implant, the interlock structurecompressing at least some of the terminal ends together in a circumferentialdirection when the implant and the implant structure are interlocked.

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